Residual pelvic rotation after single-event multilevel surgery in spastic hemiplegia

Our aim in this retrospective study of 52 children with spastic hemiplegia was to determine the factors which affected the amount of residual pelvic rotation after single-event multilevel surgery. The patients were divided into two groups, those who had undergone femoral derotation osteotomy and those who had not. Pelvic rotation improved significantly after surgery in the femoral osteotomy group (p < 0.001) but not in the non-femoral osteotomy group. Multiple regressions identified the following three independent variables, which significantly affected residual pelvic rotation: the performance of femoral derotation osteotomy (p = 0.049), the pre-operative pelvic rotation (p = 0.003) and the post-operative internal rotation of the hip (p = 0.001). We concluded that there is a decrease in the amount of pelvic rotation after single-event multilevel surgery with femoral derotation osteotomy. However, some residual rotation may persist when patients have severe rotation before surgery.     

Femoral derotation osteotomy in spastic diplegia. Proximal or distal?

We describe the results of a prospective study of 28 children with spastic diplegia and in-toed gait, who had bilateral femoral derotation osteotomies undertaken at either the proximal intertrochanteric or the distal supracondylar level of the femur. Preoperative clinical evaluation and three-dimensional movement analysis determined any additional soft-tissue surgery. Distal osteotomy was faster with significantly lower blood loss than proximal osteotomy. The children in the distal group achieved independent walking earlier than those in the proximal group (6.9 +/- 1.3 v 10.7 +/- 1.7 weeks; p < 0.001). Transverse plane kinematics demonstrated clinically significant improvements in rotation of the hip and the foot progression angle in both groups. Correction of rotation of the hip was from 17 +/- 11 degrees internal to 3 +/- 9.5 degrees external in the proximal group and from 9 +/- 14 degrees internal to 4 +/- 12.4 degrees external in the distal group. Correction of the foot progression angle was from a mean of 10.0 +/- 17.3 degrees internal to 13.0 +/- 11.8 degrees external in the proximal group (p < 0.001) compared with a mean of 7.0 +/- 19.4 degrees internal to 10.0 +/- 12.2 degrees external in the distal group (p < 0.001). Femoral derotation osteotomy at both levels gives comparable excellent correction of rotation of the hip and foot progression angles in children with spastic diplegia.     

Effect of derotation osteotomy of the femur on hip and pelvis rotations in hemiplegic and diplegic children

The purpose of this study was to evaluate hip and pelvis rotations in groups of hemiplegic and diplegic children before and after surgical correction of fixed internal rotation deformity of the hip. Twenty-two children with cerebral palsy (eight diplegia, 14 hemiplegia) having fixed internal rotation deformity at the hip were treated by multilevel surgery which included derotation osteotomy of the femur. Evaluation was done before and at a mean of 3.1 years after surgery using three-dimensional computerized gait analysis. Preoperatively, the patients in the hemiplegia group had a significantly greater compensatory external rotation of the pelvis than those in the diplegic group. Post-operatively there were no significant differences between the two groups. In the hemiplegia group the external rotation of the pelvis was corrected after correction of hip rotation by derotation osteotomy. Patients in the diplegia group showed significant improvements in the hip rotation with no significant change in the pelvis rotation after multilevel surgery.     

Multilevel orthopaedic surgery in group IV spastic hemiplegia

Most children with spastic hemiplegia have high levels of function and independence but fixed deformities and gait abnormalities are common. The classification proposed by Winters et al is widely used to interpret hemiplegic gait patterns and plan intervention. However, this classification is based on sagittal kinematics and fails to consider important abnormalities in the transverse plane. Using three-dimensional gait analysis, we studied the incidence of transverse-plane deformity and gait abnormality in 17 children with group IV hemiplegia according to Winters et al before and after multilevel orthopaedic surgery.We found that internal rotation of the hip and pelvic retraction were consistent abnormalities of gait in group-IV hemiplegia. A programme of multilevel surgery resulted in predictable improvement in gait and posture, including pelvic retraction. In group IV hemiplegia pelvic retraction appeared in part to be a compensating mechanism to control foot progression in the presence of medial femoral torsion. Correction of this torsion can improve gait symmetry and function.     

Long-term effects of femoral derotation osteotomies: an evaluation using three-dimensional gait analysis

The purpose of this study was to evaluate the long-term effects of the femoral derotation osteotomy (FDO) in the ambulatory patient with cerebral palsy (CP). The effectiveness of the FDOs were evaluated using three-dimensional gait analysis just before surgery (P0), 1 year after surgery (P1), and 5 years after surgery (P2). A total of 20 patients (27 sides) with CP were evaluated. Related physical examination and motion measures showed significant improvements at P1 that were maintained at P2. Mean maximum internal hip rotation at P0 of 77 degrees +/- 9 degrees decreased to 53 degrees +/- 8 degrees at P1 and was maintained at 58 degrees +/- 11 degrees at P2. Mean maximum external hip rotation at P0 of 21 degrees +/- 11 degrees increased to 35 degrees +/- 15 degrees at P1 and was maintained at 32 degrees +/- 13 degrees at P2. Mean femoral anteversion at P0 of 63 degrees +/- 9 degrees was reduced to 26 degrees +/- 15 degrees and was maintained at 31 degrees +/- 13 degrees at P2. During gait, mean hip rotation in stance at P0 of 20 degrees +/- 8 degrees was decreased to 2 degrees +/- 10 degrees at P1 and was maintained at 4 degrees +/- 5 degrees at P2. There were associated significant foot progression changes from an internal progression mean of 5 degrees +/- 17 degrees at P0 to -11 degrees +/- 17 degrees at P1 that were maintained at -12 degrees +/- 5 degrees at P2. The findings suggest that the FDO is a viable and lasting treatment option for the correction of anteversion and associated internal hip rotation during gait in children with CP.     

Long-term result of combination of open reduction and femoral derotation varus osteotomy with shortening for developmental dislocation of the hip

This study examined femoral derotation varus osteotomy with shortening performed on children with developmental dislocation of the hip. Each patient reached 14 years of age. Surgical outcomes were evaluated clinically and roentgenographically. We studied nine patients with 11 joints undergoing surgical repair. Age at the time of operation averaged 2 years and 1 month; the period of observation averaged 15 years and 7 months; and age at final investigation averaged 17 years and 8 months. Each patient underwent the study operation as an initial treatment. Salter pelvic osteotomy was reserved as a second treatment for those patients whose acetabular development proved inadequate during post-surgical observation. The evaluation method established by McKay was utilized to determine clinical results at the time of final investigation; 73% of the study group were established as having good results. Severin's evaluation method was used to assess roentgenographical results; 45% of the study group were determined to have good results. Kalamchi's evaluation method allowed six joints to be diagnosed with avascular necrosis of the femoral head; however, in all cases but one, necrosis had been present prior to surgery. Those six joints that did not have necrosis of the femoral head prior to surgery developed only one mild necrosis subsequent to surgery. Achieving a stable reduced position by femoral derotation varus osteotomy, as well as sufficient decompression of the femoral head by shortening osteotomy, are considered to have played very important roles in preventing the femoral head from developing necrosis.     

Mobility in Hurler syndrome

Hurler syndrome is an autosomal recessive metabolic storage disease. Hematopoietic stem cell transplant increases life expectancy, but the effects on associated musculoskeletal abnormalities remains unclear, and long-term data are limited. We detail the follow-up of 23 patients at a mean of 8.5 years after successful hematopoietic stem cell transplant.All patients underwent clinical examination at an annual multidisciplinary clinic. Serial radiological studies were reviewed to assess development and management of hip dysplasia and genu valgum.All patients demonstrated characteristic acetabular dysplasia and failure of ossification of the superolateral femoral head. Eight patients underwent bilateral pelvic and femoral derotation (mean age at surgery, 4.4 years); 4 patients had pelvic osteotomy only. Mean preoperative acetabular angle was 34 degrees. Genu valgum of variable severity due to failure of ossification of the lateral aspect of the proximal tibial metaphysis was observed early, and 6 patients underwent medial epiphyseal stapling, decreasing tibiofemoral angle by a mean of 8 degrees. Clinically, all patients were independently mobile, with restriction of internal hip rotation being the most significant clinical finding. Valgus knees and pronated feet were a typical finding.This cohort represents one of the largest available for study, and ongoing review will clarify the progression of musculoskeletal problems and determine the effectiveness of orthopaedic intervention.     

Long-term results of Chiari pelvic osteotomy in patients with developmental dysplasia of the hip: indications for Chiari pelvic osteotomy according to disease stage and femoral head shape

Background We evaluated the long-term results of Chiari pelvic osteotomy for developmental dysplasia of the hip (DDH) after follow-up of 10 years or more. The indications for Chiari osteotomy were assessed based on the results. Methods We evaluated 74 hips in 69 patients treated for DDH with Chiari osteotomy. The average postoperative follow-up period was 13 years. The mean age at the time of surgery was 32 years (range 6–64 years). The disease was classified into two stages based on joint space measurements on radiographs: an early stage (36 hips) in which the mean age at surgery was 21 years (range 6–48 years) and an advanced stage (38 hips) in which the mean age at surgery was 41 years (range 18–64 years). Femoral head shape was classified into two types based on measurements of the sphericity of the femoral head: spherical (33 hips) or flat (41 hips). Clinical manifestations were evaluated according to Japanese Orthopaedic Association (JOA) hip scores. The joint space was measured on radiographs as an index of the progression of osteoarthritis. We attempted to identify factors that affected the long-term results of Chiari osteotomy, especially in regard to disease stage and femoral head shape. Results The mean total JOA score was 72 preoperatively and 87 at final follow-up. It had improved in 66 hips and was worse in 7 hips. All of the worse cases were at the advanced stage at the time of surgery, and in 6 of the worse cases the femoral head was spherical. Hips with advanced DDH and a spherical femoral head had poor outcomes and exhibited joint space narrowing postoperatively. Conclusions Early DDH is considered a good indication for Chiari pelvic osteotomy because of the good results at 10 years or more. Even with advanced DDH, a flat femoral head predicts a good surgical outcome, but patients with a spherical femoral head may experience early progression to osteoarthritis.     

Changes in pelvic rotation after soft tissue and bony surgery in ambulatory children with cerebral palsy

The authors performed a retrospective review of pelvic rotation in 59 children with cerebral palsy who underwent lower extremity surgery and pre- and postoperative gait analysis. Two groups were studied: a femoral derotation osteotomy (FDRO) group and a soft tissue surgery only (no FDRO) group. Both groups exhibited abnormal pelvic rotation preoperatively and normalization of this abnormal pelvic rotation postoperatively. Though the mean change in pelvic rotation was small (3.3 degrees +/- 6.0 degrees), some patients demonstrated postoperative changes as large as 21 degrees. Variability in pelvic rotation was greater in the no FDRO group than in the FDRO group. Improvement in pelvic rotation occurred both in children with unilateral (hemiplegic) involvement and in those with bilateral (diplegic or quadriplegic) involvement. Surgeons planning lower extremity surgery in children with cerebral palsy should expect improvement in abnormal pelvic rotation in both hemiplegic and diplegic patients, whether or not bony surgery is planned in addition to soft tissue surgery.     

Length changes of the hamstrings and adductors resulting from derotational osteotomies of the femur.

Derotational osteotomies of the femur are frequently performed to treat persons with cerebral palsy who walk with excessive internal rotation of the hip. However, whether these procedures stretch or slacken the surrounding muscles appreciably is unknown. Determination of how muscle lengths are altered by derotational osteotomies is difficult because the length changes depend not only on the osteotomy site and the degree of derotation, but also on the anteversion angle of the femur and the rotational position of the hip. We have developed a three-dimensional computer simulation of derotational osteotomies, tested by anatomical experiments, to examine how femoral anteversion, hip internal rotation, and derotation affect the lengths of the semitendinosus, semimembranosus, biceps femoris long head, adductor longus, adductor brevis, and gracilis muscles. Simulation of derotational osteotomies at the intertrochanteric, subtrochanteric, or supracondylar levels decreased the origin-to-insertion lengths of the hamstrings and gracilis in our model by less than 8 mm (1.8%). Hence, the lengths of the hamstrings and gracilis are not likely to be altered substantially by these procedures. The origin-to-insertion lengths of the adductor longus and adductor brevis decreased less than 4 mm (1.9%) with subtrochanteric correction in our model, but the length of adductor brevis increased 8 mm (6.3%) with 60 degrees of intertrochanteric derotation. These muscles are also unlikely to be affected by derotational osteotomies, unless a large degree of intertrochanteric derotation is performed.     

Supramalleolar derotation osteotomy of the tibia, with T plate fixation. Technique and results in patients with neuromuscular disease

Torsional deformities of the tibia are common in children, but in the majority both the torsion and the associated disturbance of gait resolve without intervention. There are, however, a significant number of children and adults with neuromuscular disease who present with pathological tibial torsion, which may require surgical correction. We conducted a prospective study in two centres, to investigate the outcome of supramalleolar derotation osteotomy of the tibia, using internal fixation with the AO-ASIF T plate. A range of outcome variables was collected, prospectively, for 57 patients (91 osteotomies), including thigh foot angle, foot progression angle, post-operative complications and serial radiographs. Correction of thigh foot angle and foot progression angle was satisfactory in all patients. Three major complications were recorded; one aseptic nonunion, one fracture through the osteotomy site after removal of the plate and one distal tibial growth arrest. We found that supramalleolar derotation osteotomy of the tibia, with AO-ASIF T plate fixation is an effective method for the correction of torsional deformities of the tibia and the associated disturbances of gait in children and adults with neuromuscular disease, with a 5.3% risk of major complications.     

Subtrochanteric femoral shortening osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip

A surgical technique, which uses a transverse osteotomy, for subtrochanteric femoral shortening and derotation in total hip arthroplasty for high-riding developmental dislocation of the hip is described. Anteversion is set by rotating the osteotomy fragments, and torsional stability is augmented with allograft struts and cables when indicated. Eight patients with 9 total hip arthroplasties were followed for an average of 43 months (range, 24–84 months). Good to excellent results were obtained in 87% of patients (7 of 8). Eight of 9 osteotomies (89%) demonstrated radiographic evidence of healing at an average of 5 months. One patient had an asymptomatic nonunion of the osteotomy site but still had a good overall clinical result. Another patient suffered fatigue failure of a distally ingrown porous device, which necessitated revision total hip arthroplasty 18 months after surgery. Subtrochanteric osteotomy in total hip arthroplasty for developmental dislocation of the hip allows for acetabular exposure and diaphyseal shortening while facilitating femoral derotation. Furthermore, proximal femoral bone stock is maintained and some of the potential complications of greater trochanteric osteotomy may be avoided.     

Test of stability as an aid to decide the need for osteotomy in association with open reduction in developmental dysplasia of the hip

After open reduction for developmental dysplasia of the hip (DDH), a pelvic or femoral osteotomy may be required to maintain a stable concentric reduction. We report the clinical and radiological outcome in 82 children (95 hips) with DDH treated by open reduction through an anterior approach in which a test of stability was used to assess the need for a concomitant osteotomy. The mean age at the time of surgery was 28 months (9 to 79) and at the latest follow-up, 17 years (12 to 25). All patients have been followed up until closure of the triradiate cartilage with a mean period of 15 years (8 to 23). At the time of open reduction before closure of the joint capsule, the position of maximum stability was assessed. A hip which required flexion with abduction for stability was considered to need an innominate osteotomy. If only internal rotation and abduction were required, an upper femoral derotational and varus osteotomy was carried out. For a 'double-diameter' acetabulum with anterolateral deficiency, a Pemberton-type osteotomy was used. A hip which was stable in the neutral position required no concomitant osteotomy. Overall, 86% of the patients have had a satisfactory radiological outcome (Severin groups I and II) with an incidence of 7% of secondary procedures for persistent dysplasia including one hip which redislocated. The results were better (p = 0.04) in children under the age of two years. Increased leg length on the affected side was associated with poor acetabular development and recurrence of joint dysplasia (p = 0.01). The incidence of postoperative avascular necrosis was 7%. In a further 18%, premature physeal arrest was noted during the adolescent growth spurt (Kalamchi-MacEwen types II and III). Both of these complications were also associated with recurrence of joint dysplasia (p = 0.01). Studies with a shorter follow-up are therefore likely to underestimate the proportion of poor radiological results.     

A Dega-type osteotomy after closure of the triradiate cartilage in non-walking patients with severe cerebral palsy

A total of 47 non-walking patients (52 hips) with severe cerebral palsy and with a mean age of 14 years, (9 to 27) underwent a Dega-type pelvic osteotomy after closure of the triradiate cartilage, together with a derotation varus-shortening femoral osteotomy and soft-tissue correction for hip displacement which caused pain and/or difficulties in sitting. The mean follow-up was 48 months (12 to 153). The migration percentage improved from a pre-operative mean of 70% (26% to 100%) to 10% (0% to 100%) post-operatively. In five hips the post-operative migration percentage was greater than 25%, which was associated with continuing pain in two patients. Three patients had persistent hip pain and a migration percentage less than 25%. In five hips a fracture through the acetabulum occurred, and in another there was avascular necrosis of the superior acetabular segment, but these had no adverse effect on functional outcome. We conclude that it is possible to perform a satisfactory pelvic osteotomy of this type in these patients after the triradiate cartilage has been closed.     

Torsionsfehler an den unteren Extremitäten bei Patienten mit infantiler Zerebralparese

Patients with spastic cerebral palsy often develop torsional deformities at the level of hip, shank or foot. The abnormal muscle activity such as spasticity or the increase of tone are considered as the major cause. The present study shows that the gait pattern is another cause which may lead to deformities. The study is based on gait analysis of 13 patients and 8 normal controls. The major and significant differences in gait kinematics were toe walking, toeing-in and internal rotation at the hip in the patients whereas the unaffected control group had a physiological heel-toe gait. The difference in torsional moments at the hip, knee and ankle were statistically significant. At the knee and the ankle a decrease in the internal rotation moment was found, whereas at the hip a paradoxical curve pattern with a more externally directed rotation moment was seen. These differences in torsional moments can explain the external rotation at the foot and/or shank as well as the increase in femoral anteversion, although they might be primarily caused by the deformity itself. Because a constantly acting force, however, changes the bony form and/or shape, the abnormal moments can be considered as a factor leading to deformities. A heel-toe gait seems to be mandatory for an efficient prophylaxis. Torsional deformities at the shank require a corrective osteotomy which is performed at the supramalleolar site and fixed by an unilateral, external fixator. Malrotations at the hip usually show two components: the functional part can be corrected by lengthening and weakening the tensor fasciae latae and the ventral parts of the glutei, using stretching exercises, botulinum toxin A or operative lengthening and releases. The increased femoral anteversion needs to be corrected by a femoral derotation osteotomy. Patients with cerebral palsy show a reduced control of their legs; therefore, balance internal torsion should not be corrected to neutral and overcorrection must be avoided. A remaining slight internal rotation after correction will help to spontaneously stabilize the leg if it gives way at initial contact, by "falling underneath the centre of gravity". If the leg is in neutral or external rotation, the patient needs to realign the centre of gravity over the dynamically unstable leg, showing a trunk-lean over the leg, the Duchenne limp.     

The effects of femoral derotation osteotomy in cerebral palsy: a kinematic and kinetic study

We attempted to quantify the effects of isolated femoral derotation osteotomies using clinical evaluation and gait analysis (kinematics and kinetics) in patients with cerebral palsy (CP). Twelve children with CP were evaluated before and 10 months after isolated femoral derotation osteotomy, and 15 healthy children were evaluated as controls. There were significant improvements on clinical examination. A better position of the hip and ankle in the transverse plane was evident and significant changes occurred in terms of hip and ankle kinetics after surgery. Improvements in kinematics and hip and ankle power are very important biomechanically. The correction of lever arm dysfunction and more physiological hip and ankle power generation result in an improvement in terms of energy consumption, leading to a more functional and economic gait pattern.     

Medial rotation deformity of the hip in cerebral palsy--surgical treatment by derotation femoral osteotomy

Medial rotation deformity of the hip is a problem to patients handicapped by cerebral palsy who are able to walk, because the knees point inward during gait ("kissing patellae") and cause falls and frequent injuries, knee and ankle distorsions. The deformity is a result of an increased femoral neck anteversion. The purpose of the paper is to present the results of an original method of precise determination of the degree of rotation for derotation femoral osteotomy. Indications for this operation were set in patients with spastic form of cerebral palsy over 10 years of age, able to walk, who had difficulties in gait and whose lateral rotation was less than 15 along with the medial rotation of over 70 in the hip on the side of the deformity. Twenty hips in 17 patients able to walk were operated on. The average age was 21 (11 - 42), the average follow-up was 11 years (3-17). The assessment of the results was based on the comparison of the rotational abilities of the hip and individual problems before and after the operation. Excellent result was achieved in 12 (70.6%) patients i.e. 15 (75%) hips; good result was achieved in 3 (17.6%) patients i.e. 3 (15%) hips; unsuccessful result in 2 (11.8%) patients i.e. 2 (10%) hips. Complications aroused in 6 patients i.e. 6 (30%) hips. The conclusion is that derotation osteotomy of the femur is a successful procedure for the treatment of the medial rotation deformity of the hip in patients with the spastic form of cerebral palsy who are able to walk. The above mentioned indications must be respected and the original method of determining the degree of derotation applied. Due to a relatively high percentage of complications, e.g. osteitis, the operation is suggested to patients aged 10 to 15 when possible complications can more easily be cured.     

Recurrent hip instability after hip reconstruction in cerebral palsy children with spastic hip disease

BackgroundMigration percentage (MP) is widely used to evaluate hip stability in children with spastic cerebral palsy (CP). Orthopedic surgeons need more objective information to make a proper hip reconstruction surgical plan and predict the outcome.MethodsMedical records and plain radiographs of children with CP who underwent the hip reconstruction procedure for dysplasia were reviewed retrospectively.ResultsIn total, 253 operated hips (140 patients; 11.7 ± 3.3 years old) were included in this study. MP at pre-operative (T_pre) was 35.3 ± 22.5%; at immediate follow-up (T_post) was 5.9 ± 9.5%; at last follow-up (T_final) was 9.8 ± 10.8% (4.5 ± 2.3 years post-operative at age 16.3 ± 2.8 years). In hips with Melbourne Cerebral Palsy Hip Classification Scale (MCPHCS) grade 3 (n = 78), around 30–45% had an unsatisfactory outcome at T_post and T_final. However, hips categorized as other grades showed only 2.1–9.1% of unsatisfactory outcome. In less affected hips (pre-operative MP<30%, n = 122), 109 hips (89.3%) had varus derotation osteotomy only, the other 13 hips (10.7%) were combined with a pelvic osteotomy. In more severely affected hips (pre-operative MP ≥ 30%, n = 131), 26 hips (19.8%) had varus derotation osteotomy only, the other 105 hips (80.2%) were combined with a pelvic osteotomy.ConclusionsHips with pre-operative MP between 15 and 29% (MCPHCS grades 3) can be a higher risk group of recurrent hip instability after hip reconstruction surgery. Multiple indications beyond MP should be considered when indicating pelvic osteotomy or hip muscle release as combined procedures with varus femoral osteotomy for hip reconstruction in this milder group to achieve a consistent long-term satisfactory outcome.     

Paralytic hip instability in poliomyelitis

A retrospective study was made of the results of surgical treatment of subluxation or dislocation of the hip in patients who had suffered from poliomyelitis. Good results were achieved in 46% and satisfactory results in 24%. The key factors for success are muscle balance, the femoral neck-shaft and anteversion angles, and the acetabular geometry. Iliopsoas transfer can augment the hip abductor power by an average of one MRC grade. Varus derotation femoral osteotomy is important to re-establish a normal neck-shaft angle and anteversion. The results of pelvic osteotomy are variable and the importance of a posterior acetabular defect is emphasised.     

Idiopathic Increased Anteversion of the Femoral Neck: Radiological and Clinical Study in Non-operated and Operated Patients

The development of femoral neck angles in children with idiopathic increased anteversion was investigated. The anteversion (AV) angle in 16 non-operated patients (n = 32) decreased from a mean of 45 degrees at the age of 7.3 years (median) to 31 degrees at the age of 15.7 years. The neckshaft (CCD) angle remained unchanged.

A subtrochanteric derotational osteotomy was performed in 24 patients (n = 48) aged 7.7 years (median). The AV angle was corrected from 47 to 3 degrees, and the CCD angle from 134 to 124 degrees. At follow-up at the age of 16.5 years the AV and the CCD angles had increased to 14 and 135 degrees respectively. The internal rotation of the hip was increased to the same extent in the two patient groups. The degree of external rotation as well as total rotation was significantly larger in the non-operated patients compared to the patients who needed an operation.

At follow-up the rotational movements of the hip and the external torsion of the leg/foot were measured and compared with the corresponding measurements for a control group of 26 healthy subjects whose median age was 16.3 years. In the non-operated patients the internal rotation was reduced at a rate corresponding to the spontaneous reduction of the femoral anteversion, while the external rotation was unchanged. In the operated patients the rotational movements were normalized, as was the anteversion of the femoral neck. No differences in external torsion of the leg/foot were found in the three groups.

Based on these results we conclude that cases of idiopathic increased anteversion of the femoral neck are not corrected spontaneously as the child grows up. With a subtrochanteric derotational osteotomy slight overcorrection may be indicated, but simultaneous varus correction of the femoral neck seems to be unnecessary. The degree of external rotation of the hip determines gait symptoms in patients with increased femoral anteversion. No regular compensatory external torsion of the leg/foot develops during growth.